A triple laser flow cytometry has been developed so that various immuno-fluorescent labeling techniques may be employed for the ivestigation of tumors cell kinetics. Three laser beams at different wave lengths are made to interesect a tumor cell flow stream passing through a quartz cuvette so that multiparameter signals may be obtained. These signals are processed by specialized electronics and then analyzed by means of a PDP 11 computer. Simplified optics have increased light detection efficiency by an order of magnitude.